Electrical stimulation of primary motor cortex within the central sulcus for intractable neuropathic pain

Objective To assess the pain-relieving effects of motor cortex electrical stimulation (MCS) within the central sulcus and the predictive factors retrospectively. Methods Thirty-four patients with intractable neuropathic pain underwent MCS; 19 patients had cerebral lesions, and 15 had non-cerebral lesions. In selected 12 patients, test electrodes were implanted within the central sulcus and on the precentral gyrus. Twelve patients received both MCS and repetitive transcranial magnetic stimulation (rTMS) of the primary motor cortex. Results Pain reduction of 50% was observed in 12 of 32 (36%) patients with 12 months follow-ups (2 patients were excluded because of short follow-up). In 10 of the 12 patients who received test electrodes within the central sulcus and on the precentral gyrus, the optimal stimulation was MCS within the central sulcus. In 4 of these (40%) patients, positive effects were maintained at follow-ups. The pain reduction of rTMS significantly correlated with that of MCS during test stimulation. Conclusions The test stimulation within the central sulcus was more effective than that of the precentral gyrus. In the selected patients, chronic stimulation within the central sulcus did not significantly improve long-term results. Significance The present findings suggest that an intra-central sulcus is one of the favorable targets for MCS.